Among the classes of woodwind instruments are those known as fipple flutes, or whistle flutes, in which sound is produced by blowing air through a windway against a lip which is a relatively sharp edge. This air stream oscillates across the lip and functions with the elasticity of the air in the bore of the instrument to change internal pressures in the bore. Finger holes in the body are closed or opened to alter the pitch by changing the length of the vibrating column of air.
Whistle flutes have been used for centuries as folk instruments and presently, because of their simplicity, are being used extensively in school music education.
Whistle flutes are made in many bore configurations. The most common are the following:
The recorder is a sophisticated instrument with an extended range. Chromaticism is achieved with a somewhat complex fingering pattern. The sound lacks sonority and the production of sound requires sensitive control. The bore is conical-cylindrical.
The penny whistle is a folk instrument with a two octave diatonic scale. It has little easily usable chromaticism. The bore is ordinarily cylindrical, but may be conical.
The ocarina bore whistle flute is sometimes described as "Globular". This type of instrument has been and presently is being used in music education in spite of its faulty intonation, woefully out of tune chromaticism and limited range. The unmodified Flutophone.sup.R, for example, when tuned to A-440 has notes more than a semitone sharp.
These types of instruments are easy to blow and have simple, linear fingering patterns. Their use in music education is a reluctant compromise since ear training is an important part of music education. Pitch memory and the recognition of pitch-interval relationships are best developed if they are not contaminated by the cacophonic out of tune playing which is typical of beginning ensembles using faulty, out of tune instruments.